1. Field of the Invention
The present invention relates to a method and apparatus for surface treating the surfaces of a workpiece, more particularly, to a method and apparatus wherein the workpieces to be surface treated are continuously moved through a bed of aggitated surface treating media.
2. Discussion of the Prior Art
Various processes and apparatus are known to the art for surface treating workpieces. Examples are shown in the following U.S. Patents.
U.S. Pat. No. 2,815,609 issued on Dec. 20, 1957 shows an apparatus for deburring and polishing workpieces including a pan which holds deburring material such as steel balls o stones. The pan is mounted in a stationary frame for vertical reciprocating movement by means of sprockets and chains supported on the frame. The apparatus includes a shaft which is mounted to the frame over the pan and is moved in a reciprocating motion along its longitudinal axis by means of an eccentric. The workpiece to be deburred is clamped to the reciprocating shaft to depend therefrom, and the pan is raised so that the workpiece is submerged in the deburring material. The shaft is then reciprocated to move the workpiece back and forth through the deburring material. After a sufficient time, the pan is lowered and the workpiece is removed from the deburring material, and the deburred workpiece is removed from the shaft.
U.S. Pat. No. 2,918,926 issued on Dec. 29, 1959 shows a washing and degreasing apparatus which includes a large tank for holding a suitable liquid cleaning solution. A parts basket having perforated walls is suspended into the liquid solution in the tank. The parts basket has one open end, and is mounted on springs for vibrator and oscillatory motion. A vibration generating device which includes an electric motor is connected to the parts basket by means of a belt to impart a vibratory motion to the basket. In addition, a sloped endless conveyor is located within the tank so that a portion of the conveyor lies below the open end of the parts basket to receive the parts from the basket and convey the parts out of the tank. Parts to be cleaned are deposited in the basket near the end thereof opposite the open basket end so that they are immersed in the cleaning solution. The basket is then caused to vibrate so that the parts therein will be moved toward the open basket end and be discharged onto the endless conveyor for removal from the tank.
U.S. Pat. No. 3,045,397 issued on July 24, 1962 shows an apparatus for surface treating parts which includes a support frame mounted on springs and an electric motor connected to the support frame through a belt system for imparting a vibratory action to the support frame. The apparatus further includes a plurality of parts receiving vats rigidly mounted to the support frame. The parts to be treated as well as liquid treating agent are place in the vats, and the frame is vibrated.
U.S. Pat. No. 3,128,577 issued on Apr. 14, 1964 shows an apparatus for deburring articles of considerable length which includes a tank containing abrasive material. Vibrator devices are attached to the outer side of the floor of the tank to vibrate the abrasive material in the tank. The opposite end walls of the tank have aligned apertures for accommodating the longitudinal movement of an elongated article to be deburred through the tank. The apertures have seals to prevent abrasive material from leaking out of the tank. Powered, article feed rollers are located outside the tank at one end wall. The elongated article to be deburred is inserted longitudinally through the apertures in the tank end walls and is engaged by the feed rollers. The feed rollers move the elongated article through the tank wherein it is subjected to the vibrating abrasive material and is deburred thereby.
U.S. Pat. No. 3,148,483 issued on Sept. 15, 1964 shows a machine for the surface treatment of an article by the reaction of media in vibratory movement which includes a rigid base with a horizontal table resiliently supported on the base by coil springs and a trough containing particulate treating material is secured to the table. Vibratory movement is imparted to the table, and therefore to the trough, by means of an eccentric drive arrangement located in the base below the table. The elongated trough has an upstream end wall, spaced apart side walls, a concave floor, and is open at the downstream end. A perforated platform is located at the open downstream or outlet end of the trough to separate particulate media exiting the trough from the treated articles also exiting the trough. The separated media is returned to the upstream end of the trough through an inlet chute for reuse in the treatment of further articles placed in the trough.
U.S. Pat. No. 3,336,701 issued on Aug. 22, 1967 shows a elongated, downwardly inclined container box containing an abrasive particulate material. The elongated, sloped container box is suspended on air cushions on fixed legs. Vibration is imparted to the container box by means of driven shafts and eccentric weights located beneath the container box. Articles to be finished are loaded into the container box by a chute located at the elevated container end. The lower end of the container box includes a lip over which finished articles and particulate treating material overflow from the container box. A screen arrangement is positioned beneath the container lip outside the container box for separating finished articles from the abrasive particulate material. The particulate material passes through the screen onto a recycling conveyor which returns particulate material back to the container box for reuse.
U.S. Pat. No. 4,258,505 issued on May 31, 1981 shows another apparatus for cleaning a workpiece with abrasive particulate material which includes a closed vessel. A grate is located within the vessel above the vessel floor. A bed of abrasive material is located above and supported on the grate, and the volume beneath the grate forms a plenum chamber. Compressed air is introduced into the plenum chamber and passes upwardly through the grate to maintain the abrasive material in a fluid and agitated state. The two end walls of the vessel are formed with openings through which a continuous elongated workpiece is moved through the bed of abrasive material. In addition, air conduits are located through the bed of abrasive material next to the path of the elongated workpiece passing through the abrasive material bed. These air conduits have nozzles oriented to direct compressed air streams against the surface of the workpiece moving through the abrasive material bed. The air issuing from these nozzles pick up particles from the fluidized bed and propels the abrasive particles at high velocity against the surface of the workpiece. A mixture of air and abrasive material rising from the abrasive bed is removed from the vessel through an exhaust duct to a separator device. The separator device separates particulate material from the air. The separated particulate material is returned to the vessel for reuse, and the separated air is exhausted to the atmosphere.
U.S. Pat. No. 4,586,293 issued on May 6, 1986 shows a vibratory surface treating apparatus and method wherein a reservoir containing a bed of surface treating media is vibrated to fluidize and agitate the bed of surface treating media and workpieces to be surface treated are caused to move through the bed of surface treating media under the influence of the vibrations imparted to the reservoir. In another embodiment, this patent shows an endless belt conveyor system submerged within the bed of surface treating media for moving the workpieces through the media bed.
U.S. Pat. No. 4,662,425 issued on May 5, 1987 shows a batch type vibratory scrubbing apparatus which includes a container filled with particulate scrubbing media and vibratory generators for vibrating the container and scrubbing media. A part or casting structure is suspended by a chain above the container, and a part or casting is fastened to the bottom end of the support structure. Additional vibration generators are connected to the support structure. In operation, the support structure with the part or casting attached is lowered to locate the part or casting into the vibratory particulate media. The support structure is then raised to remove the part or casting from the particulate media.